Sear mechanism



July 17, 192s. Y A 1,617,588

W. T. GORTON SEAR MECHANISM Fil'ed July l1, 1924 3 34 @L 29 l Walter T. Enrtnn Patented July 17, 192s.

Y. WALTER T. GORTON, F THE UNITED STATES ARMY, SPRINGFIELD, MASSACHUSETTS.

"snare, MECHANISM. Y

. Application iiieapzruiy 11, 1924.. serial No.v 725,441.

(GRANTED UNDER Tini Tno'visIoNs or THE ACT or` MARCH a, 1883, 22 STAT. L., 625,.)

The invention described'herein may be manufactured and used by or for the Gov# ernment for governmental purposes without the payment to me of any royalty thereon.

My invention relates, in general terms, to

a sear mechanism designed to maintain the firing pin of a gun retracted when in cocked position. More lparticularly my invention resides in the provision of a single element with/inthe bolt which will effectively retract the firing pin and prevent its releaseuntil the breech mechanism islocked in forward position and which is so disposed with respect to a trip element that release of the firing pin will only be accomplished by a relatively long movement of the trigger effected by a correspondingly small effort.

The principal objects of my invention are: .to provide a sear mechanism embodying a single element which will automatically perform the function usually obtained by the cocking lever, sear and Sear slide with their actuating springs and holding bolts; to so construct the sea-r that a relatively small thrustwill initiate its withdrawal to inop-r erative position; to complete the withdrawal operation through the instrumentality .of the firing pin; to provide means -fcrp -isitively vinsuring retraction of the firing Ypin Aupon recoil of the bolt and to absolutely prevent the release of -the firing pin exceptv when the breech mechanism is fullyy forward and locked. Y, y l

To these and other ends,iny invention consists in the construction, arrangement, afi/id 'combination of'elementsldescribed hereinafter and pointed out in the claims forming a part of this specification.v y l n One embodiment of my invention is illustrated inthe accompanying drawings, in YVwhich, n Y

to show the arrangement of trip and scar; Fig. 2 is a horizontal section of the bolt showing the scar and firing pin in cocked position Fig. Sis a horizontal sec-tion of the bolt` showing the sear and firing pin in firing position;

Fig. 4 is a sectional view taken on the line 4-4 of Fig. 3; g.

Fig. 5 is a detailed view of the sear inA rear elevation; l l

Fig. 6 is a plan view of the sear;

Fig.V 7 is a detailedfview in side elevation I:

of the firing pin; and

Fig. 8 is a fragmentary plan view of the firing pin.

In the accompanying drawings in which like characters of referenceV ldesignate like or similar parts,

5 and 6 indicate the side plates thev re-A ceiver of a' gun to which is attached inany suitable manner a spade'grip 7. A forked y trigger 8 pivotally mounted on the spade grip 7 carries opposite lugs 9 on itsy upper portion in rear'of Athe side plates 5 and 6, which lugs are adapted for engagement with a trip element operable by the trigger. Y

`The trip elementinay conveniently be' an elongatedT bar 10, formed' at'its rear end with al laterally projecting lug l1lY adapted for engagement with a lug 9 of 'tlietriggeix lhe cross arm of theT barformed at its forward end, provides anaoutwardly pros jecting arm l2, and an inwardly projecting arm 13, which latter arniprojects through a slot 1.4L formed in the side plate -6 and is formed with a beveled end for engagement with the sear, as .willbe presently described.

The T bar is preferably mounted in a housing 1,5, which may be connected toA the side platein any suitable manner; a con# yenient vcon'nectioinias herein shown, consisting in providing a beveled lug'lG on the casing adapted to enter ya slot 17 `inthe Vsider y plate 5Aand engage the beveled rear wall of the slot. A b oltv18, formedwith a tapered head, connects the front end of the housing tothe, side plate, `the tapered head engaging the curved beveled .front wall of the slot lli and being drawn tightly there'againstlOi7 ya I1utl9.

The housing is formed with an-oli'set porl tion 2O to receive the outwardly projecting Fig. l is a top Aplan view'of a gun broken ing portion 22' which is abruptly terminatedv as at 23 and is adapted to form a cam surface for a purpose which Iwill appear hereinafter. If desired, thisf construction may be modiiedand a cam for performing va y be attached to the side similar function may plate.

' ment Ywith r 2te.. Y' l 1,677,588

A bolt adapted'. for slide-bley move- Y Vla) operationrwhen thetrigger isactuated,

eet to the side plates and! Gy is Y 'formed Wn" d uned.y exten sion 247.

its forward portionliollov/'ed'toenclose a coil spring-3G, Wiiiel-i is seated against a pinfitlYV rigidly mounted VVin the 'bolliti-i and-passing through a slot in tlieiirifng pin'29;' iTlie squared bott-onlin 33", tlieiorwardfaoe'of Wliieh is beveled as at an' angle of 4'50 to 'form a cam surface. Y* n n Y The base 'ofr-tne bolt 25' is boredA transversely'ii'oin side to'side'to embrace a, seai adapted `for slieable movement Within tbe boltf' lJne end of tbe sea r is beveled as at-S to co-actV Witlrtlle cainsnrliace 24 of tneside Vplate so' that when the bolt moves rearwardl-'yV the sem-135' will forced com# Vpletely Within the boltr QjvJliere it 1s main-v :tainedVV ini-lined'l position by tbe straight sides of the plate 6,1 r be oppositeend of the is reduced as at 37 on a plane pnralleli'to f the longiti'idinal axis of the bolt toviorm a straiglitsided lng 38 of tli'esarne Width asi the lateral lug; l1 of the trip `1,0 and having a forwardly Ye'Xtending beveled, face 339'for Contact vvitli the beveled end of thearm 18;

The upper central portion of the Sear 35 is Cut/away as` at 40', forming square Walls 4l" bave been moved to the ree to greater.depthtol form-"a bevel' sin'face 43 intermediate"V the 'v Walls 41 Aand V42"4v ,andi

which is, adapted tov icooperate'yvitli tliebevreled Jiace 34 formedl onft'beforvard portiony of 4the base 3310i the firing pin. The'rearf' "edge ofthe beveled' cam surface 431s terminated at a point which Yextends ai'slight' ,disV` tance beyond the longitudinal bore of the bolt when the Vse'ar isnormally in llocked po-. sition soy tliat. When the seal; 35' isactiiatedl by tbe trip l0', it will' on'l'ybeA necessary `for itV to be moved ar Vshort distance when the i,

cam 34 of thev firing pinafter being. cammed y,out o areurved recess 44j spaced a slight distance fromv the terminas of the cam 43V is afforded' a point of; entry againstV the camA 43 'of the sear andunder the action ofther` firing pin,Y spring, 30. completes tbe Withdrawalof" the Sear to inoperative positionv.

It desired", the-.cams 34 :and 413 may'l be formedWitlfr` slightlyY i'nel-ined or; correspondingV coneavef andi convex .surfaces to reduce vibration of the movable elements.

n base portion-2G and are@ Y l y `The forwardportwe- O' one side oli the base 26 is cut V:lvfay at 9B Y in tbe bolt 25 is a longitudinal bore in which is re- Y x, ciprocalfly mountedaa iirinlgpin);having Vito' move the'requred dfstance to enablev the the: llug1` 9'- forined thereon aetsfon` the leg i11V tbe 4tti-p51() to retract the same against-the e tripbbeai'ingbn the camsurface bf'tlie n Qthesear cams the liring pin out of S the reeess44'and moves the sear to the right saTiCien-tzdistanoe vto permit entryr of the caniv 340il the ringpin, which undertlie cornes to*Y restagainstV the side plate 5-.} WVlien Y ing portions to'ertlae reargftlief'sear@35i-Mingagainst the cam 23- of; tbe sidel plate 5 '1s n, u tbey force yof the explosionv moves the -reeoi-l-V base of the firing' pin 29 is formed with a;V

the iring pinspring until the cam gages the recess 44 and-seuiiel-ylocks the can not bereleased to tliefiri-ng' position except when tne bolt is' completelyforward and' loifflfedas only then thesear4 W-ill bei-ree firing pin to be Vfinally'ir-ihaasedI Y e If the. trigger is held back,k as for sus-r tained nre7 the forward;movement ofthebo'lt' 'trip spring'moves bothvtle trigger andthe trip -to the forward, or'inoperativer position; V-Iclaimz' Y firingpin in cocked position. The firingpin .sin

p after the irst shot islfired a-iord's tlie same 1 l. Af sear -mechansm for 'firearmsem4 bold'ying an elongatedmem-ber having bev'-Y eled ends,Y the Y upper centraliportion Ybeing f unequal-lyV recessed to prov-ide al cam surface at'ktherjuncture'oflthe inequalities Y Y p Y 2. A` Vsea-r mechanism-fior fire arms ein'- bodying an elongated 'member having beyeledj Ve'ndsftheVv upper centralportion bein-g! recessedrto Aprovide clearance for; a'i'irmg `pinvrhen fthe: saniefis beingmjovedto' cocked* Y position, and the're'ar'portiion beingfrecessed f J 1 to .receive a complemental portion ofthe' fir-ffVJ ging pinv'fhereby toY lockit cocked" posif' tion. y Y

and a tiring pin,4 of `a Sear transversely mounted in the bolt and engage-able `with the firing pin,y Yand means for movmgthe'sear,

- said sear beingradapt'ed to clear thejiringpin when the same -is 4retractedandv including means integrally formed thereon to operatively engage the-firing p-i-n whereby to retract t-liesame Whenthef bolt is moved'toithe rear. n Y 'Y Y Y 4. In a 'gun-,the combination a. bolt and a firing pin, of; a seantnansversely,

mounted in thebolt vand'fengageable*'with vthe firing pin, nsaid 'Sear being-adaptedto,` Y be manually moved arelatively shortydisr-V tance and automatically moved a relatively long distance.

5. In a gun, the combination with a bolt and a tiring pin, of a sear transversely mountedin the bolt and engageable With the liring pin, said sear ybeing formed with means for operatively engaging tbe ring pin.

6. In a gun, tbe combination with a bolt and a firing pin, of a sear transversely mounted in the bolt and engageable with tlie firing pin, said sear being formed with beveled opposite ends. l

7. In a gun a bolt, a iring pin carried by the bolt, a sear engageable With lt-lie firing pin and adapted to ride under tbe firing pin, and means for automatically forcing the sear into engagement With the tiring pin to retract the sameto inoperative position.

8. In a gun a bolt, a firing pin carrie by tlie bolt and a scar engageablevvith thek clearance for the firing pin and providing a y the firing pin to firing pin When moving Y inoperative position.

9. ln a gun` the combination with a bolt and a sear, of a Vliring pin, a spring carried by the iring pin, and means formed on the base of the tiring pinand for engaging the sear to force the same laterally with' respect to the ring pin when the firing pin yis released. Y x

10. In a gun, the combination with a. bolt and a. iiring pin, of a scar, transversely mounted in the bolt and engageable With the firing pin, and means for camming the sear into engagement with the firing pinv when the bolt is retracted.

11. In a gun, the combination with a. bolt and a firing pin, of a sear transversely mounted in the bolt and means for automatiposition.

bolt, manually operated means for initiating the Withdrawal of' the scar, and automatically operated means or completing the Withdrawal.

13. 1n ai gun, the combination with a bolt,

and a tiring pin, of a sear mounted in the bolt and capable of movement to ino-perative positiononly When the bolt is fully for- Ward.

14. In a gun, the combination With a bolt and a tiring pin, of a sear transversely mounted in the bolt, and means for positively moving it into locking position.'

15. In a gun, a bolt, a liring pin carried by the bolt and a sear moved by reciprocaton of the bolt to vlock the pin in cocked position.

16. In a gun, a bolt, a ring pin carried by tliebolt' and a sear reciprocable inthe bolt moved bv reciprocation of the bolt to lock the tiring pin in cocked position.

17. The combination with a tiring pin, of a combined scar and pin cooking element movable yat right angles to the pin.r

18. A firing pin and a sear therefor, the sear operable to cock the firing pin, and the tiring pin operating to `'release the sear after initialmovement of the Sear toward released 19. A bolt, a longitudinally reciprocal firing pin, and a transversely movable sear, said pin and sear arranged for mutual actu-` ation o each other. K,

20. In a machine gun, a combined firingpin cooking member and scar. f

WALTER T. GORTON. 

